#define _CRT_SECURE_NO_WARNINGS 1
class Solution {
public:
    int tribonacci(int n) {
        if (n == 0) return 0;
        if (n == 1 || n == 2)  return 1;

        int* dp = new int[n + 1];
        dp[0] = 0, dp[1] = 1, dp[2] = 1;
        for (int i = 3; i <= n; i++)
        {
            dp[i] = dp[i - 3] + dp[i - 1] + dp[i - 2];
        }
        return dp[n];
    }
};